21535650449 has 2 divisors, whose sum is σ = 21535650450. Its totient is φ = 21535650448.

The previous prime is 21535650413. The next prime is 21535650469. The reversal of 21535650449 is 94405653512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17028945025 + 4506705424 = 130495^2 + 67132^2 .

It is a cyclic number.

It is not a de Polignac number, because 21535650449 - 2²⁰ = 21534601873 is a prime.

It is not a weakly prime, because it can be changed into another prime (21535650469) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10767825224 + 10767825225.

It is an arithmetic number, because the mean of its divisors is an integer number (10767825225).

Almost surely, 2^21535650449 is an apocalyptic number.

It is an amenable number.

21535650449 is a deficient number, since it is larger than the sum of its proper divisors (1).

21535650449 is an equidigital number, since it uses as much as digits as its factorization.

21535650449 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648000, while the sum is 44.

The spelling of 21535650449 in words is "twenty-one billion, five hundred thirty-five million, six hundred fifty thousand, four hundred forty-nine".